Author Topic: A basic fork seal question  (Read 584 times)

Offline UncleD

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A basic fork seal question
« on: 02.11. 2018 22:35 »
58 Super Rocket...new to me and older restoration so slowly working through its ailments.

I replaced the fork oil and have found that both forks are now leaking oil from the seal holder region (slow drip onto the floor of the workshop)

There was a quantity of oil in the forks originally but probably only a fifth of what should have been.

I have not dismantled forks before so am wondering about the construction material of the seals.  Are they a fibrous material?  I assume that they may have dried out while standing / unlubricated.  Are they made of a material that may swell and seal (given a little time) now that they have been oiled or are they probably stuffed?

I don't want to begin fiddling with forks unless I have to and then I will probably do the full job since I don't know the history of the bike and although not mistreated, he has been neglected.

Cheers

Northern Territory, Australia

Online chaterlea25

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Re: A basic fork seal question
« Reply #1 on: 02.11. 2018 23:06 »
Hi,
The seals are rubber "garter" seals the same type as on most modernish bikes
The best ones have a dust lip on the outer face, rather than standard industrial seals
The BSA seal holders can trap water above the seals and corrode the legs  *sad2*

I had leaky fork seals on a modern bike that had sat idle for some time, they sealed up after some use

John
1961 Super Rocket
1963 RGS (ongoing)

Offline mikeb

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Re: A basic fork seal question
« Reply #2 on: 03.11. 2018 05:14 »
you'll have to replace the seals to stop the leaks. its not too bad a job tho you need to get a tool to remove the seals like this:
http://shop.srmclassicbikes.com/product/fork-oil-seal-holder-removing-fitting-tool-61-3005 or make your own out of a bit of pipe of the right diameter. then you need to tool (or a magic broomstick) to put the fork back up into the triple clamp. ok its a PITA getting the tools, but the job is ok. part of the joys of BSA ownership! where buying or making strange tools is a new fun weekend activity. search the forum for lots of relevant posts.
AND... when they are out make sure the forks are not pitted - if they are then the oil will find its way past the new seals. (don't ask me how i know this)
New Zealand
'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Online KiwiGF

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Re: A basic fork seal question
« Reply #3 on: 03.11. 2018 10:49 »
58 Super Rocket...new to me and older restoration so slowly working through its ailments.

I replaced the fork oil and have found that both forks are now leaking oil from the seal holder region (slow drip onto the floor of the workshop)

There was a quantity of oil in the forks originally but probably only a fifth of what should have been.

I have not dismantled forks before so am wondering about the construction material of the seals.  Are they a fibrous material?  I assume that they may have dried out while standing / unlubricated.  Are they made of a material that may swell and seal (given a little time) now that they have been oiled or are they probably stuffed?

I don't want to begin fiddling with forks unless I have to and then I will probably do the full job since I don't know the history of the bike and although not mistreated, he has been neglected.

Cheers

How much oil did you put in? The oil level is well below the seals so don’t usually leak badly even when completely shot?
New Zealand

Last had an A10 in 1976, in 2011 it was time for my 2nd one.

1956 Flash Frame EA7-168x Eng. CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

B31 “hot rod” (yeah right)

Armstrong Siddeley Whitley for rainy days (with wife).

GL1800 Goldwing not sure why yet

Online bsa-bill

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Re: A basic fork seal question
« Reply #4 on: 03.11. 2018 10:56 »
Quote
or make your own out of a bit of pipe of the right diameter.

My advise is buy the tool, I and friends have made our own and found it difficult to get correct dimension pipe and beefy enough to do the job, the bought tool is up to it and much easier to use
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline UncleD

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Re: A basic fork seal question
« Reply #5 on: 03.11. 2018 11:01 »
Kiwi...that is a very good question.  I have been wondering why it has been leaking when standing still...

I did use the quantity from the Haynes manual but could have stuffed this up.  From memory it was a tad under 200ml per fork but I'll need to check.

Northern Territory, Australia

Offline UncleD

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Re: A basic fork seal question
« Reply #6 on: 03.11. 2018 11:16 »
Manual said 213cc per fork....interestingly, it says this equates to 5.5 fl.oz....but I used a conversion App. and this say 5.5 oz (UK) equates to 156 ml.

Is this a typo or are my calculations inaccurate?


Northern Territory, Australia

Online paulmbsa

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Re: A basic fork seal question
« Reply #7 on: 03.11. 2018 11:39 »
a babys bottle is great for measuring these amounts and cheap to buy

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Re: A basic fork seal question
« Reply #8 on: 03.11. 2018 15:03 »
 There's bumper stickers around that say "is it the truth....or did you read it in the *Local Paper* " (*Local Paper* being large of a conglomerate owned by a ex-pat- Australian ), I guess the same can be said for Haynes...

 A 10 Imp.oz beer is 285ml, so 5.5 fl.oz will be 5.0oz @ 142.5ml + 0.5oz @14.25  equals 156.75ml =5.5fl.oz.   

 (for those who like fractions *smile*;142,1/2ml+1/2oz @14,1/4ml)=156,3/4)

 For US users,  213ml =;  *eek*   *conf2* smaller *beer* 

 **Edit* Hour or so later....the Haynes is a bit confusing- even their 4oz/100cc is 25cc/Fl.oz contradicting a general ~28.5 ml/Fl.oz...maybe they allowed for density of ~90% , so 213 cc would be ~7.5 fl.oz - typo option sounds good *conf2*

 It's no comparison, but I think my Conical forks take 190cc per side, I'd expect yours to have slightly more volume......so 213 doesn't sound too wrong  *dunno*

Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Swarfcut

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Re: A basic fork seal question
« Reply #9 on: 03.11. 2018 16:54 »
   To  keep it simple,  30ml is more or less 1 fl oz.

   Swarfy

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Re: A basic fork seal question
« Reply #10 on: 03.11. 2018 17:41 »

 
Quote
To  keep it simple,  30ml is more or less 1 fl oz.

 Yeah sure- good enough for a vague estimate, but if people are fed the wrong information, that becomes 'not simple' too....I used the 10oz beer example because it was a simple conversion to 5.5 ...and arrived at much the same 156ml figure as U-D instead of 165...

                   *beer*........................... *beer*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online chaterlea25

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Re: A basic fork seal question
« Reply #11 on: 03.11. 2018 18:58 »
Hi All,
I got totally confused with US measurements during my recent trip there  *pull hair out* *pull hair out*

When you asked for a beer or coffee they wanted to know how heavy you wanted it to be  *conf2* *conf2*

 *lol* *lol*
John
1961 Super Rocket
1963 RGS (ongoing)

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Re: A basic fork seal question
« Reply #12 on: 03.11. 2018 19:48 »
G'day fellas.
1 US oz = 29.57ml, 1 UK oz = 28.41ml.
To confuse it even further
1 US gallon = 3785.41ml, 1 UK gallon = 4546.09ml
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Re: A basic fork seal question
« Reply #13 on: 03.11. 2018 22:54 »

 In adddition (reckon I have addd ?  *smile*) to above, for those of us who've forgotten;

 1 US pint = 16 oz = 1Lb (pound)    1 US pound = 8Lbs / 128 oz



 1 Imperial Pint =20 oz              1 Imperial gallon = 10 Lbs 160 oz

 8 Pints = 1 gallon  both  Imp. pints & US pints

 The US Pint/Gallon is based on what the British system was until the 1820's when it was revised for the Gallon to weigh 10 Lb, probably to simplify shipping and storage calculations among other reasons. 

 The US didn't adopt it, probably due to having not much earlier escaped the clutches of the Empire   *fight*

 There's a lot more to it, but that's the essence of what I learned when I looked it up  a couple of years ago, and probably nothing new to many...... *conf2*



Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

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Re: A basic fork seal question
« Reply #14 on: 04.11. 2018 03:25 »
G'day fellas.
Getting a bit off topic but I think I made the rod for my dampers 1 cubit long (including threads).
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7